The invention is based on an apparatus for injecting a fuel-gas mixture defined hereinafter. From German Patent Document 36 09 798 A1, an apparatus for injecting a fuel-gas mixture is already known in which the fuel is fed through a fuel injection valve into a first end of a cylindrical mixing conduit of a mixing tube. The gas is blown through a gas delivery conduit that discharges into the first conduit end and strikes the injected fuel. This produces a two-phase flow or in other words a fuel-gas mixture made up of the fuel and the gas. However, this apparatus has the disadvantage that a considerable portion of the fuel settles on the cylindrical wall of the mixing conduit n the form of a fuel film, which is only partly entrained by the fuel-gas mixture flowing past it and runs along the wall of the mixing conduit, so that the fluid-gas mixture contains only a relatively small proportion of liquid fuel. The fuel is inadequately atomized, and a largely homogeneous mixture formation is not assured. Moreover, the danger exists that for a certain injection quantity, the fuel that has collected on the cylindrical wall of the mixing conduit may suddenly tear away and form an undesirable fuel-gas mixture that is only inadequately atomized when it reaches the intake tube.